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Using bamboo residue and high-density polyethylene (HDPE) as the main raw materials, core–shell structured wood plastic composites (WPCs) with nano-CaCO3 filling shell were prepared by coextruded technology. The effect of nano-CaCO3 contents on the flexural properties, impact strength and dynamic thermo-mechanical properties of the core–shell structured WPCs were investigated. And the value of core–shell interface interaction parameter was calculated by dynamic thermodynamic parameters. The results showed that the flexural strength increased by 48.1% and 40.3% when it was loaded with 10%–15% nano-CaCO3, compared to the HDPE shell composites, respectively. While nano-CaCO3-filled HDPE shell had lower impact strength in comparison with HDPE shell, the field emission scanning electron microscope revealed proper interfacial adhesion between the core and shell layers. The storage modulus of core–shell structured WPCs increased as nano-CaCO3 contents increased, but the values were lower than that of the HDPE shell. Addition of nano-CaCO3 caused an increase in the glass transition temperature (Tg) of the core–shell structured WPCs, loss factor (tanδ) of the core–shell structured WPCs decreased. The value of the core–shell interface interaction parameter of the core–shell structured WPCs increased significantly after the nano-CaCO3 loading reached 15%, which was consistent with the bending test results. These findings demonstrate that the core–shell structured WPCs have excellent properties filling with nano-CaCO3 in the shell layer, and bamboo residue is added to the core layer. [ABSTRACT FROM AUTHOR]

Nanocalcium carbonate (CaCO) was successfully adhered to the surface of bamboo fiber (BF) via both impregnation and blending modification. The BF-, BMBF (bamboo fiber treated by blending modification)- and IMBF (bamboo fiber treated by impregnation modification)-reinforced high-density polyethylene (HDPE) composites were all manufactured by means of extrusion molding. The flexural and impact properties of the composites (the addition of BF, BMBF and IMBF were all 30 wt%) were analyzed. CaCO with a loading of 15 wt% had an effect on the performance of the composites. The flexural strength (FS) of the BMBF and IMBF composites increased by 1.09 and 9.36%, respectively, while the differences of the impact strength were insignificant among these, compared to the BF/HDPE composites. The flexural properties of the IMBF/HDPE composites were investigated with different mass fractions of IMBF (5, 10, 15, 20, 30, 50, 60 and 70 wt%). The results showed that the FS of the IMBF/HDPE composites reached a maximum value (58.99 MPa) when the mass fraction of the IMBF was 30 wt% and increased by 50.95% compared to when the mass fraction was 5 wt%. These results were supported by ESEM and fractal dimension analysis in terms of proper distribution of nano-CaCO and interfacial adhesion between the IMBF and HDPE matrix. The results revealed that the fractal dimension D of IMBF/HDPE composite with a mass fraction of 30 wt% reached a maximum value (2.2036), which was similar to the FS results. There was a linear correlation between lg (FS) and fractal dimension D, indicating that the fractal dimension was practicable for the IMBF-reinforced HDPE composites. The fractal features could reflect the macro-mechanical properties, and the percentage error of the fitting function was within 10%. [ABSTRACT FROM AUTHOR]

Core-shell structured bamboo-plastic composites (BPCs) were directly prepared with a single-screw/single-screw coextruder system. The effects of different shell layers, such as high-density polyethylene (HDPE), bamboo pulp fiber (BPF)/HDPE, and white mud (WM)/HDPE, were studied in the context of the mechanical properties and the characteristics of the interfacial transition zone (ITZ) of BPC. The mechanical properties of the core-shell structured BPC were characterized by flexure, short-beam shear, and impact tests. The surface morphologies of BPC were analyzed with field emission scanning electron microscopy. The ITZ properties were studied with dynamic mechanical analysis and nano-indentation testing. The results show that the flexural properties, shortbeam strength, and impact strength decreased profoundly in the presence of BPF or WM. The dynamic mechanical analysis results suggest that the ITZ properties decreased, as indicated by the reductions in the storage modulus, loss modulus, and loss factor; the nano-indentation results show that on the addition of BPF or WM, a gradient in the hardness and modulus of elasticity appeared across ITZ. [ABSTRACT FROM AUTHOR]

Abstract To investigate the effect of manufacturing method on thermal and flammable performance of CaCO 3 impregnation modification (IM) treated bamboo pulp fiber (BPF) composites. The composite was made from HDPE with BPF contents of 30 wt% and 50 wt% by hot press molding (HPMP), extrusion molding (EMP) and injection molding process (IMP). The results showed that the E′ , crystallinity index (CrI) and heat distortion temperature (HDT) of the composites manufactured by EMP were highest. IM had a slight positive effect on E' and CrI of BPF/HDPE composites. The HDT of composites increased when the fiber content increased, leading to an increase in the heatproof property correspondingly. Compared to the samples manufactured by HPMP and EMP, the samples manufactured by IMP were extremely ignitable and flammable. Nano CaCO 3 could improve the flame retardancy performance of samples manufactured by EMP effectively and the fiber content had an effect on the flame retardancy performance of samples, especially the samples treated by nano CaCO 3. The average mass loss rate demonstrated a similar trend to the peak heat release rate for all composites. IM was more effective for EMP to improve the thermal stability and flame retardancy of composites compared with HPMP and IMP. Highlights • The composites were manufactured successfully by HPMP, EMP and IMP. • The E′ , CrI and HDT of the samples manufactured by EMP were highest. • The CrI of IM-BPF/HDPE composite was higher than that of BPF/HDPE composites. • The samples manufactured by IMP were extremely ignitable and flammable. • IM and fiber content had a different effect on composites manufactured by HPMP, EMP and IMP. [ABSTRACT FROM AUTHOR]

Abstract A thermoplastic-penetrated natural fiber belt was developed for potential application in filament winding. Discontinuous sisal fiber bundles were impregnated with high density polyethylene and then connected into continuous pre-pregs via hot-pressing. The interfacial bonding was improved by treating the fibers with sodium hydroxide (NaOH) and three types of coupling agents (NH 2 C 3 H 6 Si(OC 2 H 5) 3 , C 2 H 3 Si(OC 2 H 5) 3 and C 51 H 112 O 22 P 6 Ti). Tensile properties of the fiber bundles, pre-pregs, and annular specimens were determined. The fiber surface microstructure and the pre-preg interfacial bonding were evaluated via scanning electron microscopy and Fourier transform infrared spectroscopy. Among the four treatments, 2% C 2 H 3 Si(OC 2 H 5) 3 yielded the most significant improvement in the tensile properties of the pre-pregs and annular specimens. The fiber bundle was less damaged by the coupling agents treatment comparing to NaOH treatment. When the overlap at the end of the sisal fibers was >11 mm, the presence of the joint had no effect on the tensile strength of the pre-preg. The pre-preg belt containing treated fibers, which was evaluated based on the requirements of filament winding applications, exhibited a high performance. [ABSTRACT FROM AUTHOR]

• BPC provides an environmental friendly way to dispose the bamboo residue. • Fractal theory and DMA can quantificationally analyze the interfacial interactions. • D and loss factor hybrid model built the relation between macro and micro property. • IM had an interactive effect with preparation technics on interfacial interactions. In order to study the relationship between the interfacial adhesion and preparation technology, nano CaCO 3 impregnation modification (IM) as an efficient way was reported for improving the interfacial interactions, using three preparation technologies which include hot press molding (HPMP), extrusion molding (EMP) and injection molding process (IMP) to produce the bamboo pulp fiber (BPF) reinforced HDPE composites. Fractal theory and dynamic mechanical analysis were used to investigate the interfacial interactions quantificationally. The fractal dimension D of composites was different, indicating the D did characterize the difference among the different complicated fracture surfaces. A poor correlation (R2 = 0.4563) was observed between three preparation technologies and D , indicating there are remarkable difference between HPMP, EMP and IMP. The apparent activation energy was lower in the IM-BPF/HDPE composites (e.g. 115.99 kJ/mol for EMP-2 <124.88 kJ/mol for EMP-1). The least potential energy was needed to change the structure of the composites prepared by EMP, which indicated that the interfacial adhesion of composites prepared by EMP was the best while the HPMP was the worst. It can be concluded that IM had an interactive effect with preparation technology on interfacial interactions of the composites and IM worked more effectively on composites prepared by EMP. [ABSTRACT FROM AUTHOR]